The invention relates to a casting machine system and to a process for producing hybrid metal/plastic articles. In the present context, hybrid metal/plastic articles are understood to mean articles which consist of metal and plastic and are produced by firstly casting a precursor product from one of the two materials and then subjecting the precursor product to a second casting process, in which it is provided with the other material. By way of example, a metal piece can firstly be produced as a precursor product in a metal-casting process, e.g. by means of die-casting, and this can then be encapsulated with plastic, partially coated with plastic or have plastic molded onto it in a corresponding plastic-casting operation, e.g. a plastic injection-molding operation. Alternatively, a plastic part may firstly be produced as a precursor product in a plastic-casting process, and the metal can then be molded onto it in a metal-casting process.
It is prior art, for example, to produce metallic precursor products at a first site and to transfer these by freight to a second site, where the hybrid article is produced from the precursor product by use of the second casting process. In this case, the second casting process does not take place in any time correlation with the first casting process, but instead takes place, for example, days or weeks later, possibly with intermediate storage of the precursor product.
Alternatively, it is prior art to produce hybrid articles of this type within a single machine having relatively complicated molds in order to provide both at least one metal-casting cavity and at least one plastic-casting cavity. In relation to this, mention should be made, for example, of laid-open publications EP 1 718 451 A1, JP 06-246783 A and JP 2000-280277 A. In a further hybrid casting machine of this type, as is disclosed in laid-open publication WO 2005/053930 A1, a temperature monitoring system is additionally implemented, and this includes the measure of measuring the temperature of the precursor product obtained in the first casting process and transmitting it to a control system, which controls the second casting process depending on this temperature information. In this case, the first casting process can be a metal-casting process, but alternatively also a plastic injection-molding process, and this is followed by the second casting process as a plastic injection-molding process or metal-casting process.
The technical problem underlying the invention consists in providing a casting machine system and an associated process for producing hybrid metal/plastic articles, which make it possible to produce hybrid articles of this type with a comparatively flexible casting machine utilization and relatively low costs and/or in a relatively short time.
The invention solves this problem by providing of a casting machine system for producing hybrid metal/plastic articles, including (a) a first casting machine and a separate second casting machine, wherein the first casting machine is a metal-casting machine and the second casting machine is a plastic-casting machine, or the first casting machine is a plastic-casting machine and the second casting machine is a metal-casting machine; (b) a transfer device for transferring a precursor product, produced by a first casting process in the first casting machine, to the second casting machine, in which a hybrid metal/plastic article is formed from the precursor product by a second casting process; and (c) a temperature-regulating device for regulating the temperature of the precursor product in a controllable manner after its removal from the first casting machine, and before starting the second casting process. The invention also includes a manufacturing process for producing hybrid metal/plastic articles, including the following acts: (a) casting a precursor product by a first casting process in a first casting machine; (b) removing the precursor product from the first casting machine; (c) controllably adjusting the temperature of the precursor product removed and transferring said precursor product to a second casting machine; and (d) carrying out a second casting process using the precursor product, introduced into the second casting machine, in order to form a hybrid metal/plastic article, wherein the first casting machine is a metal-casting machine and the second casting machine is a plastic-casting machine, or the first casting machine is a plastic-casting machine and the second casting machine is a metal-casting machine.
The casting machine system according to the invention includes a metal-casting machine and a plastic-casting machine as two separate, i.e. independent, casting machines. This makes it possible to use the two machines flexibly also when required for a different purpose, i.e. in order to produce pure metallic cast pieces or pure plastic injection-molding products. On the other hand, it is possible to avoid a greater outlay on transport/freight by erecting the two casting machines at the same production site. A transfer device ensures the transfer of the precursor product, obtained in the first casting process, to the second casting machine, in which the desired hybrid metal/plastic article is then formed from the precursor product by way of a second casting process.
The casting machine system includes a temperature-regulating device designed so as to be able to regulate the temperature of the precursor product in a controllable manner after it has been removed from the first casting machine, before it is subjected to the second casting process. In the present context, the term “temperature regulation” is to be understood as meaning active heating and/or cooling, which can be suitably selected in each case, of the precursor product by an appropriately provided heating or cooling apparatus. Depending on the requirement and application, the ability to control this temperature regulation may relate to an open-loop control or, alternatively, to a closed-loop control of the relevant temperature-regulating process or of the temperature of the precursor product. This makes it possible to produce corresponding hybrid metal/plastic articles, e.g. by means of the inventive manufacturing process.
In one structurally and functionally advantageous refinement of the invention, the temperature-regulating device is a fully or partially integrated constituent part of the transfer device. In a further refinement of this measure, the transfer device includes at least one workpiece carrier on which the precursor product can be placed, and the temperature-regulating device includes, as an integral part of the workpiece carrier, a temperature sensor unit and/or a temperature-regulator for actively heating or cooling the precursor product. This makes it possible for the precursor product to be held at a desired temperature in a controlled manner as it is transferred from the first casting process to the second casting process.
One refinement of the invention utilizes residual heat. For this purpose, the temperature-regulating device can include a residual heat utilization device which can utilize residual heat of the hybrid article, after it has been produced in the second casting process, to heat a precursor product obtained in each case in the first casting process.
In one refinement of the invention, the temperature-regulating device includes a detector and/or monitoring for a temperature of the precursor product after it has been removed from the first casting machine. This can contribute to an advantageous, controlled temperature regulation of the precursor product after it has been removed from the first casting machine.
In one development of the invention, the precursor product can be subjected to a corresponding processing process in a processing station, before it is moved into the second casting machine. The temperature-regulating device is used to hold the precursor product at a desired temperature higher than room temperature before, during and/or after this processing process. In this case, the processing process can also be an assembly process or include such a process.
The casting machine system includes a processing station for receiving the precursor product removed from the first casting machine and for carrying out a predefinable processing process during a cooling phase, during which the precursor product is cooled from a temperature at the end of the first casting process to a lower, predefinable desired temperature before the start of the second casting process. This desired temperature has a temperature value which is predefined higher than room temperature. This measure makes it possible to subject the precursor product to the relevant processing process during a time period required for cooling before the second casting process is carried out, as provided in the inventive manufacturing process, as a result of which the overall duration of the production of the hybrid component can, in turn, be optimized. For this purpose, it can be ensured that the processing process is stopped as soon as the precursor product has reached the predefined desired temperature. Temperature regulation within the context of active heating and/or cooling is not absolutely necessary in this case, but can optionally be provided, for example in order to hold the precursor product at the desired temperature for a certain time longer.
In one refinement of the invention, the desired cooling temperature is between 60° C. and 190° C., as a result of which it is possible to ensure optimum linking or adaptation to the subsequent second casting process.
In one development of the invention, the transfer device includes a handling robot. This robot can be used to transport the precursor product in a very convenient and automated manner, including removal from the first casting machine and/or movement into the transfer device and/or movement into an optional processing station and/or into the second casting machine.
In one refinement of the invention, a metallic precursor product is produced in a metal-casting machine in the first casting process, a sprue of this metallic precursor product being left at least until it has been completely transferred into the second casting machine. The sprue can thereby be utilized for handling purposes during the transfer, for example. In a further refinement, the metallic sprue can be encapsulated by injection molding with plastic material by the second casting process, in order to thereby form a hybrid metal/plastic article having a corresponding form.
Advantageous embodiments of the invention are shown in the drawings and are described in the text which follows.